This section describes approaches that could be employed, but are not necessarily approaches that have been previously conceived or employed. Hence, unless explicitly specified otherwise, any approaches described in this section are not prior art to the claims in this application, and any approaches described in this section are not admitted to be prior art by inclusion in this section.
Existing routing protocols assume recalculation of routes can be performed in response to a detected failure (e.g., loss of a link or a connecting network node); however, recalculation of routes requires computation time that likely results in a loss of data traffic. One attempt to accelerate responding to a detected failure includes “Loop Free Alternates” (LFA), where a router can respond to losing a next hop router in a path to a destination node by identifying a feasible successor for reaching the destination node, as long as the feasible successor does not create a loop by sending the packet back to the router. The IETF Draft by Atlas, entitled “U-turn Alternates for IP/LDP Local Protection (draft-atlas-ip-local-protect-uturn-00.txt)”, illustrates in FIG. 3 of the IETF Draft a network topology where LFA solutions can be provided for the network nodes N2, N4, and R3 to forward a data packet to the destination node D in the event of a failed link, however, LFA cannot provide any solutions for any of the network nodes N3, S, P, R1, or R2. The IETF Draft by Atlas proposed a “U-turn protocol” to reverse a link; however, the U-turn protocol cannot provide any solution for the nodes P, R1, or R2 of FIG. 3 in the event of a link failure.
Another proposed routing protocol, referred to as “Fast Local Rerouting for Handling Transient Link Failures” (FIR) requires a complete recalculation of routes in response to a link failure, and hence recalculation of routes requires computation time that likely results in a loss of data traffic.